The present invention concerns security protection within an integrated circuit design and pertains particularly to detection of a single event upset detection and protection in an integrated circuit.
For some processing applications, it is essential to operate in a secure environment so that operations cannot be probed or altered. In the prior art, various methods have been used to provide for a secure processing environment.
For example, a mechanical chassis can be used to house processing equipment. This mechanical chassis can include tamper switches and other elements to detect and protect against tampering and alterations. Unfortunately, such a mechanical chassis can add a significant amount of expense to a product.
Alternatively, in order to restrict access to particular integrated circuits, the integrated circuits can be covered with epoxy or other chemical materials to hinder access. Unfortunately, often this can be easily defeated and so provides only a nominal amount of protection.
Another method to provide for a secure processing environment is to implement the system on a single integrated circuit. A portion of the integrated circuit, for example, can be used to perform secure operations. However, there may still be attempts to defeat this arrangement.
For example, an attacker may attempt to expose information about a security key or information about a security system by applying radiation or alpha particles in the proper location. The excess radiation or alpha particles can result in a single event upset (SEU). The single event upset can affect the data integrity of a secure operation. If the single event upset occurs in an operation related to a security key or data encrypted with the security key, this may weaken the effectiveness of the protection within the integrated circuit and perhaps provide an avenue to break the security system.
In order to protect against such an attack by radiation and alpha particles, analog circuitry could be added to an integrated circuit which measures the actual radiation levels and high frequencies. However, this is very expensive and not an efficient solution for a low cost digital system.